Currently available continuous glucose sensors are inaccurate and prone to failure, making the goal of an artificial pancreas elusive. Furthermore, their designs are not patient-friendly and they require frequent user input (e.g. calibration). The largest hurdle in developing implantable glucose sensors is the foreign body response (FBR). In this Phase I SBIR, we propose a syringe-injectable, tissue-integrating, glucose sensor to mitigate the foreign body response and enable accurate glucose monitoring for a minimum of 3 weeks in the body. PROFUSA's long- term goal is to develop a self-calibrating, implantable CGM with a minimum operational life of 3 months and a longer-term goal of 12 months that will be sufficiently accurate so as to enable an artificial pancreas. Tiny, soft and porous tissue-integrating biosensors that encourage capillaries to grow in and throughout the entire cross section of the sensor are being developed to allow reliable sensor function and thus overcome limitations of the FBR. Prototype sensors will be produced by integrating luminescent sensing nanospheres (glucose-responsive and reference nanospheres) into previously developed vascularizing hydrogel scaffolds (developed by PROFUSA and collaborators through currently active grants). The near infrared sensor signals are read through the skin with a miniaturized Continuous Optical INterrogation (COIN) patch reader that utilizes novel micro-optics to significantly decrease background noise. The goal of this Phase I SBIR is to demonstrate in vivo sensor functionality with the sensor and reader prototypes. Advancements towards a thin-film patch reader that will continuously and discretely monitor blood glucose will improve patient compliance. Clinical translation of this technology will motivate and enable diabetic patients to more tightly control their glucose levels without fear of hypoglycemia, and will reduce the diabetes disease burden on the healthcare system.